Individuals having certain medical conditions may undergo chest physical therapy to aid with lung drainage and airway clearance. Such medical conditions include cystic fibrosis, bronchiectasis, neuromuscular diseases (e.g., Guillain-Barré syndrome), progressive muscle weakness (e.g., myasthenia gravis), and tetanus. Individuals having lung diseases, such as pneumonia, bronchitis, and certain forms of chronic obstructive pulmonary disease (“COPD”), including chronic bronchitis, may also benefit from chest physical therapy.